Communications cables are used throughout the world for transmitting information over long distances. These cables are exposed to many conditions which can damage the core including heat, cold, snow, and rain, in addition to thermal shocks caused by lightning strikes and power surges. To protect against these conditions and prevent the migration of moisture through the cable, a protective woven fabric is commonly wrapped about the core of the cable and acts as a barrier layer against the aforesaid conditions.
The prior art discloses a number of methods of protecting communication cables. Examples of thermal barriers include a multi-ply, thermally stable cladding as short-term protection from high temperatures for the cable core, wrapping the core with a tape sheath of a film or glass cloth impregnated with a fluorinated polymer for improved low smoke and flame retardant properties, or embedding a flame retardant material in the outer plastic cable component for flame retardancy. Examples of water blocking barriers include a water absorption tape composed of a fibrous tape coated with an adhesive and sprinkled with a water swellable powder wound around the outer surface of a spacer in a metal protective tube arrangement, a cable jacketing containing at least one wrap of a backing and facing web with a unique slightly crosslinked aromatic water polymer sandwiched between the two webs, or filling the voids in a cable core with water blocking material. U.S. Pat. Nos. 4,913,517 and 5,373,100 both disclose wrapping water absorptive yarns around critical parts of the cable.
U.S. Pat. No. 5,131,064 issued to Arroyo et. al., herein incorporated by reference in its entirety, discloses a communication cable having a lightning protective thermal barrier layer and a water blocking capability provided by a laminate comprising both a high temperature resistant tape and at least one other tape with a superabsorbent water swellable powder therebetween. In a preferred embodiment, the thermal barrier is constructed of woven glass fabric laminated to and in between two layers of a spunbonded non-woven polyester web with a superabsorbent powder disposed between the polyester webs and the center woven glass. The cable wrap barrier material is manufactured in a wide width and subsequently slit into the desired narrow tape widths depending on the diameter of the cable.